Pressure adjustable foam support apparatus

ABSTRACT

The present invention concerns a mattress-like apparatus whose firmness is adjustable by the user. This goal is attained by enclosing the polyurethane foam core of the mattress within an airtight cover chamber, and varying the negative air pressure (vacuum) applied into it. As a result, the mattress is adjustable as to firmness measured in terms of Indentation Force Deflection (IFD, or spring-back force) and support (density).

FIELD OF THE INVENTION

The present invention concerns a mattress-like apparatus whose firmnessis adjustable by the user. This goal is attained by enclosing thepolyurethane foam core of the mattress within an airtight cover chamber,and varying the negative air pressure (vacuum) applied into it. As aresult, the mattress is adjustable as to firmness, measured in terms ofIndentation Force Deflection (IFD, or spring-back force) and support(density). Indentation Force Deflection is a measure of the load bearingcapacity of flexible polyurethane foam. IFD is generally measured as theforce (in pounds; 1 pound=0.453 kg) required to compress a 50 squareinch (1 square inch=6.45 square centimeter) circular indenter foot intoa four inch thick sample, typically 15 inches square or larger, to astated percentage of the sample's initial height. Common IFD values aregenerated at 25 and 65 percent of initial height.

More specifically, the present invention teaches the modulation of theprincipal characteristics of open-cell, flexible polyurethane foam foruse in support devices such as mattresses, sitting furniture, cushionsand all other applications using a support apparatus. Thesecharacteristics are subjective tactile softness and bodyweight-carryingsupport firmness, the modulation of which is effected in a way so as togreatly enhance comfort and to offer an infinite choice of easilyadjustable levels of comfort to the user at lower comparable cost. Onits own, in combination with multi-chamber arrangements and alsointegrated with known, traditional techniques, this invention enhancesthe versatility of support devices, allowing for a great number ofvariations in the choice and adaptation of materials and mattressarchitecture to go together with self-inflating, modulable foam.

BACKGROUND OF THE INVENTION

Various attempts have been made to control the hardness, softness, andsupport of foam within a mattress. This has been achieved by addingdifferent pieces or zones of foam within a mattress, each zone having adifferent density and IFD rating which corresponds to a body part suchas head, shoulders, middle body, legs and feet. Yet other inventionshave interchangeable foam components which the user may select andarrange as desired. This process is inconvenient, since bulky foamcomponents have to be stored and manipulated very often to make therequired changes. Another dilemma with “foam zones” having different IFDratings for different parts of the body, is that it is difficult to giveadequate support to a very soft foam component. To achieve this,mattress manufacturers use a coil, foam base, or compressed air baseswhich are firm and offer needed support, subsequently they layer softerfoams above said firm base to offer comfort.

U.S. Pat. No. 2,779,034 to Arpin discloses a firmness adjustment formattresses involving a standard coil spring mattress wherein standardcoil springs are enclosed by a loosely fitting airtight cover. InArpin's device, the firmness of the mattress increases while airpressure within the covered is lowered.

U.S. Pat. No. 3,872,525 and U.S. Pat. No. 4,025,974 to Lea discloses aself-inflating air mattress/mat including an airtight flexible envelopewhich encloses a core of resilient, open cell, lightweight foammaterial, substantially the entire upper and lower portions of which arebonded to the envelope. The air within can be removed by compressing thestructure whereby the foam layer collapses, allowing the mat to berolled up into a compact package.

U.S. Pat. No. 4,944,060 illustrates a mattress having a plurality ofdiscrete, air permeable cells which are to some extent hydrophobic. Theinvention uses pressurized air to inflate the mattress.

U.S. Pat. No. 6,098,378 discloses a method of packaging a singlemattress to a small size to be conveniently carried. In this method andapparatus, the foam mattress is compressed to fit into a hard containerfor shipment. At the point of sale, the mattress is extracted andexpands to its original shape.

In recent years, we have seen the advent of higher density foams such asvisco-elastic foam that solves the problem of support and softnesscombined in foam of one single piece. Visco-foam offers support becauseof its high density (typically over 3 pounds per cubic foot density−1cubic foot=0.028 cubic meter) and feels soft and desirable to the userbecause it typically has an IFD of 15 lbs or under. However, the highcost, bulk and heavy weight of a visco-foam core remains a problem.Companies, who sell visco-foam mattresses, are obliged to deliver andinstall them at the customer's home.

DESCRIPTION OF THE INVENTION

The present invention addresses these difficulties through controllingsoftness and support of foam directly, without loss of support andwithout excessive weight or bulk of the resulting mattress.

The present invention teaches how to control and adjust the principalcharacteristics of open-cell flexible polyurethane foam in a specificintegration with airtight covers and pressure valves for the use in anyform of comfort support device, for instance, mattresses. The principalcharacteristics pertain to industry standards of subjective tactilesoftness in the sense of espousing body contours so as to optimallydistribute pressure points of a person reclining on a planar surface,and of bodyweight-carrying support firmness. They are controlled andadjusted in a way to not only greatly enhance comfort, but particularlyto offer an infinite choice of easily adjustable levels of comfort,defined as a balance between softness and firmness. This is done atlower comparable cost and weight compared to high density foam varietiessuch as visco-elastic foam, and in combination with known, traditionaltechniques, it enhances versatility, allowing for a great number ofvariations in the choice and adaptation of materials to go together withself-inflating, modulable foam into comfort level adjustable supportdevices.

The invention teaches how the Indentation Force Deflection (IFD) anddensity properties of a certain quality range of flexible open-cellpolyurethane foam are adjusted by removing some of the air from withinthe foam cells and altering the cellular density of the foam core. Sincehigh density, more expensive foams, such as visco-elastic foams, arevery desirable as to comfort, the main teaching of the invention is howto modulate comparatively less expensive, lower density foam to exhibitthe feel-characteristics of high density foam, and also attain supportand comfort levels of a higher density, more expensive foam,- withoutlocking the user into a single, fixed comfort level.

IFD and density adjustment are achieved by altering open-cell, flexiblepolyurethane foam or material of similar characteristics within a fixedframework of controllable valves and airtight bladders. This art teachesthat the material is fashioned in a particular form and that it is of astructure as to permit the extraction of air in the alveolate structurein a uniform manner throughout, thus increasing material density equallyuniformly. A further feature of the material is that, by virtue of itsstructure, particular manufacturing and finishing processes, it affordsin its low IFD number modulated state a commensurably higher supportstability, heretofore only associated with foam or similar material of avery much higher density and greatly higher price. Finally, it is muchlighter in weight than the latter and can also be reduced in size andvolume for easy transport and storage.

The application of the principles of this teaching extends to a greatnumber of possible combinations of foam only and foam plus traditionalsupport devices used in the architecture of, for example, mattresses,that users may adjust to their personal preference But in all itscombinations, the pivotal point of the invention is that specificallyfashioned types of foam will soften when air is extracted from theircell structure. Compared to its original firmness, which is indicated bythe manufacturer's IFD number, its resilience will decrease to abouthalf of its original value. The density on the other hand increasesconsiderably to about double its original value, creating the muchneeded body support a mattress should have. Density of foam is itsweight per cubic foot, hence the heavier a cubic foot of foam weighs,the higher will be its density rating.

The present invention teaches that removing air from a foam core reducesthe volume of the core, hence increases its density without addingweight to the overall mattress, which would be undesirable for the user.One of the disadvantages of high density foams, such as visco-elasticfoam, is that they are very heavy and difficult to fashion in the formof a mattress. In this invention the single foam core mattress as wellas its combination with other bedding materials are much lighter ofweight but yet exhibit the same comfort and support characteristics as,for instance, a visco-elastic mattress. It has the additional advantageof being adjustable. Removing air from visco-elastic foam or similarmaterials in the same manner is not possible, because their cellularstructure is very tight and would solidify almost immediately(densification).

In the basic configuration, this invention takes the form of amattress-like support apparatus comprising

-   -   one core of open-cell, self-inflating flexible polyurethane        foam, said polyurethane foam core having an Indentation Force        Deflection value within a range of 22 to 50 lbs at standard        atmospheric pressure;    -   one airtight cover chamber enclosing said foam core, said        airtight cover chamber having at least one valve arrangement for        evacuating air;    -   characterized in that said mattress-like support apparatus is        operated by the user at sub-atmospheric pressure, in that said        foam core has a thickness of at least four inches at standard        atmospheric pressure, and in that said Indentation Force        Deflection value decreases while air pressure within said        polyurethane foam core is lowered.

The apparatus may further comprise at least one vacuum pump connected tosaid valve or valves for evacuating air.

In another embodiment, the polyurethane foam core has a density valuewithin a range of 1.2 to 2.5 pounds per cubic foot at standardatmospheric pressure, and said density value increases while airpressure within the polyurethane foam core is lowered.

In still another embodiment, the polyurethane foam core is verticallysubdivided into at least two longitudinal or transversal core sections,and the airtight cover chamber is replaced by separate individualairtight chambers for each core section, each individual airtightchamber having at least one valve arrangement for evacuating air. In analternative embodiment, the polyurethane foam core is verticallysubdivided into at least two longitudinal or transversal core sections,and the airtight cover chamber is subdivided in individual airtightchambers for each core section by internal airtight walls, eachindividual airtight chamber having at least one valve arrangement forevacuating air. Each core section may have different Indentation ForceDeflection values at standard atmospheric pressure -from the other coresection or sections. In addition, the polyurethane foam core or coresections may comprise two or more layers of self-inflating flexiblepolyurethane foam. In an embodiment, at least one of the foam layers hasa different Indentation Force Deflection value at standard atmosphericpressure from the other foam layer or layers.

The valve arrangement attached to the airtight cover chamber or to theindividual airtight chambers may comprise one or more air permeabledistancing elements, keeping any adjacent materials from obstructingairflow through said valve arrangement. Said valve arrangement may alsocomprises a spring-mounted mechanism that allows some air to return intothe foam core and thereby prevents compression set within the foam core.

The following is a description of how a polyurethane foam core changesin this present invention, demonstrated on a sample of a twin-sizemattress foam core. Such a sample typically contains a volume of about13 cubic feet of air, has an initial density rating of 1.2 and an IFDnumber of 40, corresponding to a relatively firm-surface foam weighing15.6 lbs. In comparison, visco-elastic foam of the same size wouldgenerally weigh about 58 lbs.

To effect the change in the sample, a fan-style vacuum generator isconnected to an outer airtight cover, drawing approximately 0.6 cubicfeet of air per second. At this rate it takes 3.5 seconds to double thefoams density and to reduce the IFD value so that it feels like a 2.4density high resilient foam with an IFD value of about 22. The vacuumpump is equipped with variable speed control and remote control memorysettings, so that the user can either set or recall a previous settingof an individual comfort level at the speed and in increments which suithim. In laboratory experiments, a user was made to recline on the foamin it's original configuration. He then adjusted the density and IFDsettings within the foam core. It was observed that the user's heaviestbody-parts sank into the foam and were contoured progressively as thedensity increased and the IFD value decreased. No collapsing of themattress, bottoming-out or hammock effect occurred. If no air wereallowed to re-enter the foam core and the user were to be lifted off it,the negative mould of his body with all corresponding heavy and lightpressure points would be imprinted in the foam permanently.

The second point of importance to be noted is that the foam core gainsin stability when air is removed, as opposed to an air chamber whichwould simply deflate and become wobbly, that is, unstable. In laboratoryexperiments a further point has been addressed, dealing with theundesirable characteristic of open-cell flexible polyurethane foam tosolidify in a full vacuum-state, the so-called ‘compression set’ (CS).If too much air is removed from the cellular structure of foam, it willharden in its densest state and subsequently no longer be able toself-inflate and regain its loft, even partially. CS becomes criticalwhen foam has been compressed for an extended period of time. If,however, a residual amount of air could be left in a foam core and becontrolled, it would not suffer CS nearly as much as opposed to a fullydeflated foam core.

The chamber's vacuum in this example is controlled by valves whichoperate under spring pressure. When air is evacuated from aself-inflating foam core within a hermetically sealed cover, the foammaterial's cellular elasticity exerts pressure to expand to its originalform by drawing air back into its open cells, developing a measurablesuction force. The more air is removed from the foam cells, the higherthe foam core's re-inflation force. Springs in the valve assembliesconnected to the partially emptied chamber oppose the re-inflation forcereciprocally. Hence a balance between the opposing forces can beestablished, depending on the spring force and the suction force. Testsconducted in a laboratory environment show that CS can be prevented in atotally deflated foam core if the re-inflating force is slightly greaterthan the closing force of the valve spring. In this manner, air is drawnback into the mattress at a very slow rate, and stops entering themattress when the re-inflation force of the foam equals the compressionforce of the spring in the valve. A fixed spring-force setting, allowingfoam to re-inflate to a specific degree greatly reduces the occurrenceof CS and preserves the deflated product from malfunctioning whenallowed to re-inflate after extended storage periods. The principle ofresidual air retention to off-set CS has been validated in laboratoryexperiments for polyurethane foam used in a wide variety of mattressarchitectures, be it by itself or in a combination with otherarrangements. To balance the closing force of the valve spring withinthe valve assembly against the re-inflating force of the various foams,a great number of specific compression values are being used to adapt tofoams having different IFD and density ratings.

Thus, controlling compression set forms integral part of the invention,which would not be able to perform satisfactorily over long periods oftime if intentional or accidental excessive deflation took place,destroying the specific characteristics of open cell, flexiblepolyurethane foam, which are the basis of comfort level adjustment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 4 shows a hermetically sealed, modulable foam core in its simplestform, one or more valves and a distancing element.

FIG. 5 shows the effect of pressure on a chamber containing aself-inflating foam core;

FIG. 6 shows the effect of removing weight from the core in FIG. 5

FIG. 7 shows one autonomous airtight chamber two foam cores, a singlevalve and a distancing element;

FIG. 8 shows two airtight individual chambers, one or more foam cores,an internal airtight wall, two valves and two distancing elements;

FIG. 9 shows two separate individual airtight chambers, one or more foamcores an outer attachment, two valves and two distancing elements;

FIG. 10 shows three airtight individual chambers, one or more foamcores, two internal airtight walls, three valves and three distancingelements;

FIG. 11 shows five airtight individual chambers, one or more cores offoam in each chamber, four internal airtight walls, five valves and fivedistancing elements;

FIG. 12 shows three separate individual airtight chambers, a fasteningelement, one or more foam cores, three valves and three distancingelements;

FIG. 13 shows an overall valve assembly installed in a chamber wall;

FIG. 14 shows a vacuum hose engaged in a valve with an air permeabledistancing element behind the valve, and a foam core with an explodedouter cover;

FIG. 15 shows an exploded view of the valve subassembly in combinationwith a vacuum hose;

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 4 shows one airtight cover chamber (40) and one foam core (41).Chamber (40) contains a self-inflating foam core (41) and is fitted withone or more valves (42), penetrating wall (44) of the chamber. Thevalves, when opened, either serve to let the core self-inflate rapidlyor to evacuate some air, contracting the foam core(41) in a uniformmanner and changing both its density and IFD values as the cellularvolume of the foam cells changes. Air can be extracted with a vacuumpump (not shown) connected to the valves (42) which contain an airpermeable distancing element (43). This element is essential to theproper functioning of the mattress and keeps wall (44) and valve (42)distanced from the foam core (41), hence permitting an effective airflowto and from the foam core.

As to the vacuum pump, no particular specifications are put forward forsuch an apparatus other than that it has to be efficient in extractingthe air contained in the foam core. The utilization of a vacuum pump isstated here once and not repeated in subsequent descriptions of mattressconfigurations, but implied.

FIG. 5 shows the advantage of modulating a self-inflating, open-cell,flexible polyurethane foam core in support structures such as mattresseswhen weight is placed upon it. Compared to traditional mattressarchitecture with coils and air chambers, the weights (V) are causing aquite different reaction or counter pressure. When they are placed on apartially deflated foam core (FS1), which is enclosed in a chamber (51)fitted with a valve (52), through which air can be evacuated selectivelyand uniformly, the foam core resists the pressure of the weights Wwithout sagging (hammock-effect) and deforms at local pressure pointsonly. If more air is evacuated from the core, the weights slowly sinkdeeper into the surface, still confined locally and precisely in thearea where they are exerting downward pressure, without deformingadjacent areas. Because of an increase in density and a decrease of theIFD value within the foam, the surface will become softer and offercontinuous support—unlike standard coil spring mattresses, where anyweight deposited on the surface tends to tension and harden the coilsprings, which want to return to their original, more relaxed state.

FIG. 6 demonstrates the effect with reference to FIG. 5. Foam core (FS1)is enclosed in a hermetically sealed chamber (as is shown in FIG. 4),from which some air has been uniformly removed, and the valve orplurality of valves (62) were then closed. The depressions on the topsurface, where one of the weights (W1) has been removed, can still beseen, because the self-inflating foam recovers slowly, reacting to thereduction in pressure by rearranging the internal air distribution witha flow through its open-cell structure towards the indented area. Ifadditional air were to be removed from the foam core, the depression(W1) would remain, because the resilience force of the foam cells in thedepressed area would not be strong enough to extract air from theopen-cell structure of the adjacent foam cells for an even distribution.In this state the foam core has a very reduced IFD and a greatlyincreased density, thus adopting the properties of a visco-elasticmemory foam. This example can be translated directly to the effect of aperson reclining on top of the foam core, as air is removed uniformlyfrom the chamber. The heaviest pressure points of the body are modulatedfirst, provided the foam core is fully enclosed. Any evacuation of airout of the core will result in a softer surface behaving in the mannershown in FIG. 6. For the invention at hand to perform in a satisfactorymanner, foam cores should be at least 4 inches thick.

FIG. 7 illustrates a mattress consisting of one airtight cover chamber(71) with two self-inflating pieces of foam (72) placed inside, one ontop of the other, forming a single foam core. At least one valve (73)with air permeable distancing element (74) is fitted to the outer wallof chamber (71), through which air can be exhausted or admitted. Whenthe valve is opened, air can be withdrawn from the chamber by means of avacuum pump, which will change the air volume within the foam core. Whenthe foam pieces (72) are compressed, their surfaces will soften as aresult of decreasing IFD. Provided foam pieces are used with differentfactory pre-set density and IFD values, their characteristics willchange differentially upon air evacuation. A harder pre-set foam on thebottom will soften less and provide more stability, while a softerpre-set foam on top will soften more readily under the conditions of anidentical partial vacuum. More comfort modulation levels are thusprovided to the user. The foam core in each chamber can be subdividedinto two or more core pieces, each piece of foam may or may not have adifferent pre-set foam density. All foam pieces within the same core andin the same chamber will react differently on extraction of air.

Additionally, having multiple and diverse factory-preset foam pieceswithin a chamber, signifies that the user can choose which surface ofthe mattress he prefers to recline upon before any modulation takesplace. Versatility is thus increased. Using, for example in the twochamber configuration, one or more foam pieces per chamber, it ispossible to achieve a comfort modulation level of very soft to softer inthe first chamber, and hard to very firm in the second chamber. Forclarity's and brevity's sake, the possibility of using multiple corefoam pieces per chamber and multiple chambers is implied in thesubsequent descriptions of chamber configurations, and not limited tothe present examples.

FIG. 8 shows a mattress (81) comprising an airtight cover chambersubdivided in two individual airtight chambers (A and B) by an internalairtight wall (83), each containing one or more self-inflating foampieces (84). The chambers (A&B) are both fitted with one or more valves(85) to exhaust air selectively and independently from within the foamcores. The valves penetrate the wall (81) to the interior of theirrespective chamber and both have an air permeable distancing element(86) attached to their inward end to prevent foam or cover material fromclogging the air passage. When the air is exhausted from the chambersselectively, the two cores increase in density, so there is no loss ofsupport, and they will soften because of a decrease in IFD. They will doso differentially when foam types of a different factory pre-set densityand IFD value are used, so that the foam in chamber (A), for example,can be independently modulated to give a harder surface feeling than thelower piece of foam or vice versa. On the other hand, when only the airis evacuated from the foam core of chamber (A), only this chamber willbe rendered softer because the core (B) will remain unaffected. Thismattress combination can be used on both sides, and is intended for useby two users who wish to modulate their own side of the bed selectively.

FIG. 9 shows a mattress comprising two individual airtight chambers (Aand B), both containing one or more foam pieces (92). Both chambers (Aand B) are removably connected by an exterior element (93) such as azipper or hook and loop. Although the modulation capabilities of thismattress are identical to the previous in FIG. 8, it has the addedadvantage of separating into two mattresses which can be used in adifferent location.

FIG. 10 shows a mattress comprising an airtight cover chamber subdividedin three individual airtight chambers (A,B,C) with two internal walls(101). Each individual airtight chamber contains one or more foam pieces(102, 103, 104) to form three foam cores within the three chambers whichmay or may not contain foams of similar IFD and density ratings. Threechambers thus organized, represent a comfort zone for the head (A),middle body (B), and feet (C). Each section may be modulated by removingsome air through the valves (106) (one shown) which each contains an airpermeable distancing element (107) (one shown) directly behind it, toprevent any occlusion and to increase airflow to and from the chambers.The top foam pieces in chambers (A,B and C) (108) may be softer IFDfactory-preset rated foam, and the bottom pieces (109) may be firmerfactory-preset rated foams. In this manner, the user may chose torecline on either side of the mattress (arrows 110,111), beforemodulation with a vacuum pump is commenced.

FIG. 11 shows a mattress comprising an airtight cover chamber subdividedin five individual airtight chambers (A,B,C,D and E) with four internalwalls (1101-1104). Each individual airtight chamber contains one or morefoam pieces (1105) (only one foam core shown) to form five foam coreswithin the five chambers which may or may not contain foams of similarIFD and density ratings. Five chambers thus organized represent comfortzones for the head (H) and shoulders (S), middle body (M), and feet (F).Each chamber may be modulated by removing some air through the valves(1106) (one shown) which contains a permeable distancing element (1107)(one shown) directly behind it, to prevent any occlusion and to increaseairflow to and from the chamber. As in FIG. 10, the top foam pieces inchambers (A,B C,D and E) may be softer IFD factory-preset rated foam,and the bottom pieces may be firmer. In this manner, the one may use themattress on either side.

FIG. 12. shows a mattress comprising three individual airtight chambers(A, B and C), each containing one or more foam pieces (1201) (only onecore shown). All three chambers (A, B and C) are removably connected byan exterior element (1202) such as a zipper or hook and loop at theedges of the chambers. As with previous foam combinations, this mattresscan be modulated by removing some air through the valves from eitherchamber resulting in a higher density, lower IFD more desirable foamfeel. The chambers are zoned for head (H), middle body (M) or feet (F),and have the added advantage of separating into three sections.Moreover, both foot and head sections may be inclined at differentangles if placed on an adjustable bed frame.

FIG. 13 shows an example of valve assembly as installed in the walls ofany of the chambers referenced above, with an air permeable distancingelement behind the valve. To this end, chamber wall (1308) is placedbetween two elements (1304-and 1305) of the overall valve assembly. Theflange (1304) is a truncated, inverted cone. Flange (1305) is also atruncated, but outward facing cone, which exactly matches inverted cone(1304). Once these elements are screwed together they will securelyclamp the chamber wall. Welding or gluing can also be used, while aclamped valve could be taken apart again for servicing, if necessary.Also shown is a lateral cylindrical extension (1 303) whichinterconnects to the valve and acts as an air-permeable distancingelement (1301). The element has an air-permeable opening (1302),essential for the modulation of the foam core, since air can pass to andfrom the foam core. When air is rapidly evacuated through the assembly,foam and outer cover material is prevented from occluding or touchingthe valve, because the air-permeable distancing element keeps the foamand outer cover material at a distance from the inner valve. When not inuse, the valve assembly can be closed by a plug (1306) which is insertedinto the interior of the valve assembly. The plug is attached to thevalve housing by a loss-prevention cord (1307). It also prevents anyundesirable foreign particles or liquids from entering.

FIG. 14 shows the air-permeable distancing element (1401) that maycontain additional frontal openings (1402). When the vacuum isactivated, air is drawn through the valve (V) and from within the foamcore (1403). This causes the valve, distancing element (1401), and outercover (1405) to be drawn towards the foam core (1403). By contrast, airalso passes through openings (1402) from within the distancing element(1401), thus sucking the outer cover (1405) through the openings (1402)only in that area. The outer cover wall (1405) is pulled towards theopenings (1402) and because of this vacuum effect the outer cover (1405)pulls the distancing element and the valve back towards itself. The twoopposing forces (the valve and distancing element being pulled towardsthe foam, and the outer cover pulling these components back) allow for aperfect vacuuming effect to be formed and they create a perfect airflow.Thanks to this functionality the airflow within a vacuum pump is moreefficient, causing less heat and fatigue to the electrical motor. Italso increases the speed at which a mattress can be modulated. When avacuum pump is activated to remove some air without an air-permeabledistancing element, valve (V) and outer cover (1405) would be drawntowards the foam wall (1403) and form a counter vacuum whereby verylittle air would be removed from the foam core. Also shown in FIG. 14 isa vacuum hose (1406) and nipple (1407), which can be disengaged from thevalve, or may be permanently attached to the valve extending towards avacuum pump (not shown), and may be removably connected to that vacuumpump.

FIG. 15 shows the structure of the example valve assembly in an explodedview. The chamber material is clamped between flanges (1304) and (1305).Flange (1304) is connected to a cylindrical extension (1501), which haslateral air apertures (1502) so that the air being evacuated can easilyenter the inner valve assembly. The cylindrical extension (1501) fitstightly within the air-permeable distancing element and extendslaterally (1401). Behind the valve stem-head (1503) is a compressionspring (1504) and a protective plug (1306), which has a forwardcylindrical extension (1505) with a locking slot (1506), allowing plug(1306) to be engaged into interior receptacle (1509). When air isevacuated from any of the chambers referenced above, plug (1306) isremoved from the valve assembly and nipple (1507) is being inserted intothe interior receptacle (1509) with its forward end (1508) in a pressfitting manner. A vacuum hose (1510) is attached to the nipple (1507) byway of screw threads (1511).

1-11. (cancelled).
 12. A mattress-like support apparatus comprising acore of open-cell, self-inflating flexible polyurethane foam, saidpolyurethane foam core having an Indentation Force Deflection valuewithin a range of 22 to 50 at standard atmospheric pressure; and anairtight cover chamber enclosing said foam core, said airtight coverchamber having at least one valve arrangement for evacuating air;characterized in that said mattress-like support apparatus is operatedby the user at sub-atmospheric pressure, in that said foam core has athickness of at least four inches at standard atmospheric pressure, andin that said Indentation Force Deflection value decreases while airpressure within said polyurethane foam core is lowered.
 13. Theapparatus of claim 12, wherein said polyurethane foam care has a densityvalue within a range of 1.2 to 2.5 lbs per cubic foot at standardatmospheric pressure, and wherein said density value increases while airpressure within said polyurethane foam core is lowered.
 14. Theapparatus of claim 12 wherein said polyurethane foam core is verticallysubdivided into at least two longitudinal or transversal core sections,and wherein said airtight cover chamber is replaced by separateindividual airtight chambers for each core section, each individualairtight chamber having at least one valve arrangement for evacuatingair.
 15. The apparatus of claim 12, wherein said polyurethane foam coreis vertically subdivided into at least two longitudinal or transversalcore sections, and wherein said airtight cover chamber is subdividedinto individual airtight chambers for each core section by internalairtight walls, each individual airtight chamber having at least onevalue arrangement for evacuating air.
 16. The apparatus of claim 14,wherein at least one of the core sections has a different IndentationForce Deflection value at standard atmospheric pressure from the othercore section or sections.
 17. The apparatus of claim 15, wherein atleast one of the core sections has a different Indentation ForceDeflection value at standard atmospheric pressure from the other coresection or sections.
 18. The apparatus of claim 12, wherein saidpolyurethane foam core comprises two or more layers of self-inflatingflexible polyurethane foam.
 19. The apparatus of claim 14, wherein saidpolyurethane foam core sections comprise two or more layers ofself-inflating flexible polyurethane foam.
 20. The apparatus of claim18, wherein at least one of the foam layers has a different IndentationForce Deflection value at standard atmospheric pressure from the otherfoam layer or layers.
 21. The apparatus of claim 19, wherein at leastone of the foam layers has a different Indentation Force Deflectionvalue at standard atmospheric pressure from the other foam layer orlayers.